Refrigeration system condenser arrangement



Dec. 19, 1967 L. K. QUICK REFRIGERATION SYSTEM CONDENSER ARRANGEMENT Filed Aug. 24, 1965 INVEN'TOR. 4CCS76ZZ Q0/64 United States Patent O 3358,469 REFRIGERA'IIGN SYSTEM CONDENSER ARRANGEMENT Lester K. Quick, 600 Hward St, Eugene, Oreg. 97402 Filed Aug. 24, 1965, Ser. N0. 482,142 16 Claims. (Cl. 62-196) ABSTRACT OF THE DISCLOSURE A condenser arrangement for a closed cycle refrigeration system for reclaiming heat to accomplish space beating and for maintaining head pressure under varying conditions wherein -a heat-reclaiming condenser is selectively placed in series between the compressor discharge and a full capacity heat-rejecting condenser of the system for heating and such heat-rejecting system condenser has plural coils in parallel with valving for successively connecting and disconnecting such coils for varyi.ng the condensing capacity to maintain head pressure, with one such eoil always remaining in the system and adapted to be flooded to maintain head pressure even under extreme conditions.

This invention relates to a refn'geration system and in particular is directed to improvements in the condenser arrangement of a refrigeration system employing a multiplicity of separate evaporators operated by a central compressor means such as for a modern supermarket installation.

In many supermarket installations employing a central compressor system the heat load produced by the refriger ated fixture evaporators is used to heat the interior 0f the building during appropriate seasons by circulating air past the refrigeration systern condenser and discharging the heated air into the supermarket. However, at other times of the year When space heating is not desired, the heat extracted from the condenser must be dissipated to the atmosphere. While arrangements have been developed for modulating the air flow from the atmosphere or store, past the condenser and then to the store or atmosphere as required, these arrangements have been found to be ex- .pensive and somewhat difi1cult to obtain the proper control. Other arrangements employing separate interior and exterior air cooled condensers and diverting or modulating refrigerant flow therebetween requires that both condensers be of a suflicient capacity for condensing the full refrigerant load resulting in excessive costs and an unnecessary duplicity of components. Moreover, the valving and piping of such arrangements become extremely complex and costly, as well as diflicult to properly size and install particularly in situations where the interior or space heating condenser is remotely located frorn the compressor and exterior condenser. These difiiculties are greatly magnified when it is desired to heat separate zones or buildings by reclaiming the heat developed by the refrigeration system.

Another difficulty which is encountered with a refrigeration system cf this type is controlling the head pressure within the desired 0r optimum range in spite of the vast fluctation in the demands of the system and in the ambient conditions. This is particularly true when an air cooled condenser is used for dissipating the unwanted heat of the system and yet the general desirability of using air cooled type condensers is well-known to the industry. The vast difierence in climatie conditions encountered in various parts of the country has resulted in the necessity of speci-ally designiug and engineering the heretofore conventional condenser arrangements to match the climatic conditions Which has prevented standardization of the arrangements. While there are well-known control arrangements for maintaining the desired head pressure in the refrigerant system regardless of the ambient conditions to which the condenser is subjected, such arrangements require a nearly complete flooding er filling of the condenser With the resultant requirement that an excessive amount of refrigerant must be provided in the system to permit this flooding under these periodically occurr-ing adverse conditions. Moreover, the possible beneficial affect of any sub-cooling which could be derived frorn condenser flooding is usually lost by reason of past methods of controlling the head pressure, which required the introduction of hot gaseous refrigerant t0 the outlet of the condenser thereby heating the sub-cooled refrigerant.

Accordingly, it is a principal object of this invention t0 provide a novel condenser arrangement for a refrigeration system wherein the heat may be reclaimed or dissipated to ambient -as desired and is capable of operating under all ranges of ambient conditions while maintainiug the desired head, final er last condenser and liquid line pressures.

Another object of this invention is to provide a novel condenser arrangernent for selectively reclaiming the heat developed in a refrigeration system wherein interior and exterior condensers are connected in series to permit the reclamation of any desired quantity of heat and the auto matic dissipation to ambient of the balance of the heat by the exterior condenser.

A further object of this invention is to provide a novel form of condenser arrangement wherein multiple separate condenser coils are connected in series flow relationship for heat reclamation and in a final stage parallel flow relation for disconnecting each separate condenser eoil as required to adjust the capacity of the complete condenser thereby mamtaining the desired liquid line pressures in the system.

A still further object is to provide such a multiple eoil condenser arrangement in the final stage wherein at least the first of such coils to be closed ofl is used to sub-cool the liquid refrigerant produced by the remaining condenser coils. Still another object of this invention is to provide Such a multiple eoil condenser arrangement wherein the maximum extent of flooding which will occur is the capacity of the last of the condenser coils left connected in the system thereby reducing the quantity of refrigerant used in floodiug to a mere fraction of that normally required by a condenser cf the same total capacity.

A further object of this invention is to provide a novel refrigeration heat reclaiming condenser which may be incorporated in a multizone heating and air conditioning system without the necessity cf dissipating any heat from that heat reclaiming condenser.

A further object of this invention is to provide a novel arrangement in a refrigeration system for controlling both the head pressure and the liquid line pressure regardless of ambient 01' load conditions whereby Optimum operation is achieved.

Other and more detailed objects and advantages of this invention Will be apparent from the following deseription and the accompanying drawing which is a diagrammatic illustration of the preferred embodiment of this invention.

For eonvenience, the system of this invention has been illustrated and will be described as the type of system which might be iucluded in a supermarket although it is to be understood and will readily appear to those skilled in the art that the. system can be readily adapted to other iustallations. The roof of the superruarket is schematically shown to illustrate the separation between the exterior atmosphere 11 and the interior space 12 which requires heatiug or air conditioning.

With reference to the refrigeration system itself, a surge-type refrigerant receiver 13 is connected through a large base conduit 14 formiug a gas-separating haruber having a T-connection -With a liquid refrigeraut conduit 15 between a coudenser assembly and a conventional subcooler 16 to a liquid header 17. The header 17 serves to conduct liquid refrigerant to each cf the brauch conduits leading to an evaporator coil associated with a refrigerated fixture. Three evaporator coils 18, 19 and 20 a1e showu for illustratiou purposes but it Will readily appaar to those skilled in the art that numerous other evaporat0r coils will normally be onnected in the sarue manner. Evaporators are provided with conventional control means such as expansion valves 21 and uuder normal refrigefating operatious are connected through the threeway valves 22 to a suction header 23 returning the evaporatcd refrigeraut to the intake 0'f the refrigeratioxi system corupressor 25. The aforemeutioued sub-cooler 16 is operated only wheu adequate sub-cooliug is uot accomplished by the hereinafter described condenser arraugement and theu ouly to the degree uecessary t0 preveut flash gas froxu occurriug in the liquid header 17. The subcooler 16 may be of the type employiug an evaporator coi1 surrounding a conduit conuection between liquid lin'e 15 and liquid header 17 with such coil being provided with an expausiou valve 26 and the outlet of the coil being provided with aback-pressure modulating valve 27 which is respons'ive to the temperature of the refrigeraut leaving the sub-cooler and eutering header 17. From modulatiug valve 27 the outlet of the sub-cooler is counected through lille 28 to the suction header 23.

Although it i's not esseutial to this inventiou, it has become somewhat conventional in thes refrigeration system installatious to utilize the so-called bot gas defrosting fec'hnique' for the evaporator coils and this is shown in the drawiug by the defrost gas header 29 which is connected from the upper ortion of the receiver 13 to the three-way outlet valves 22 of the evaporators. Evaporatot coil 20 is illustrated as being defrosted in this mauuer With the valve 22 conuecting the defrost gas header 29 to the coil to pass refrigerant gas from the upper porti0u of the receiver through the coil and thence through a by-pass conduit 30 into the liquid header 17. A check valve 31 is provided in the by-pass headcr 30 to preveut revers'e flow therethrough uudcr normal l'efriger21ting conditions' which would abort the operation of the expansion valve 21. In order to provide an inceutive for the flow cf defrostiug refrigerant fron1 the evaporator coil into the liquid header 17, a normally open solenoid valve 32 is provided in liquid header 17 and is operatecl to a closed position during the defrostiug of any of the evaporators of the system. A by-pass conduit ha'ving a pressure regulator valve 33 is conuected to liquid header 17 ou either side 0f solen'oid valve 32. Pressure regulating valve 33 establishes a pressure differeutial thereacross to create a sufliciently 10W pressure in liquid line 17 to accept the defrosting refrigerant and, for exarnple, a pressure drop of 20 p.s.i. abross regulator valve 33 has beeu found satisfactory. The system as thus far described forms no art of the subject inveution but is described as one exarnple of the eutire operable refri'geration system.

The-condeus'er arrangement of this iuvention is illus trated and Will n0w be described as operatiug uuder intermediate cliruatic oonditions when space hea-ting may be required in certaiu areas and uot required in 0ther areas and wheu the ambient atmospheric conditions are such as uot to cause either excessively high or 10W outside condeuser pressures. Iuside or iuterior coudenser is used herein to designate condeuser coils utilized for heat reclaiming purposes and outside or exterior condeuser is used to desiguate final stage condensing although such coudenser coils may be positioned in any housing stracture designed -to dissipate the heat of rejection t0 ambient. The variations of the positions and operation cf the various coutrol means for the coudenser aruaugement of the preseut inveution under more severe climatic conditious will be described hereinafter as appropriate. The discharge 35 0f the compressor 25 is connected through a four-way valve 36 to a discharge header 37. The discharge header 37 is couuected to any desired number cf brauch oouduits 38 leadiug to iuterior condensers employed for heatiug the iuterior 12 of the buildiug by reclaiming the heat reruoved by the operation of the evaporators 18, 19 and 20 of the system. Two interior condenser coils 39 and 40 are illustrated in the drawing as connected in parallel to brauch conduits 38 leading from discharge header 37, but it is to be understood that any number of condenser coils may be conuected to this parallel relationship as is required to accomplish the heatiug in the various spaced or remote zoues or areas of that building or even buildings in the near viciuity. For example, in the illustrated systern the condenser coil 39 ruay be associated with the oifice space of the buildiug while the condenser coil 40 may be associated With the ruain heatiug and air couditiouing unit, geuerally designated 41, for properly ventiliating and controlliug the temperature of the public portion of the super-market. The uuit 41 includes air circulatiou rneans as described hereinafter, and the c0ud6nse1' 39 has air circulatiou means 39'. Separate three-way valves 42 and 43 are connected between the brauch conduits 38 and the coudenser coils 39 and 40, respectively, and the valves 42 and 43 are separately coutrolled by thermostats 44 and 45, respectively associated with the particular spaces requiring heat so that hot gaseous refrigeraut is selectively diverted through the condensers 39 and 40 in response to a heat deruaud actuation of the valves 42 and 43 by the thermostats. As illustrated in the drawiugs, the thermostat 44 reflects that the space does u0t require beating thereby closing the valve 42 to isolate the coudeuser o0il 39 from the brauch conduit 38. In coutrast, thermostat 45 reflects the need for heat whereby valve 43 is open between brauch conduit 38 and coudenser coil 40 to pass the entire bot gas discharge from the compressor 25 through condeuser 40 to reclaim the maximum available heat if so desired. The outlets of the condenser coils 39 and 40 are counected through pressure regulatingvalves '46 and 47, respectively and check valves 48 and 49, re-

spectively, so a header 50 leading to the exterior condeuser assembly, generally designated 51. The check valves 48 and 49 preveut the flow of refrigeraut in a reverse direction iuto the -coudenser coils 39 and 40 as might occur uuder certain conditions such as when the, three-way inlet valves 42 or 43 are closed to brauch conduits 38 and the eutire refrigerant discharge of the compressor is diverted 0r by-passed to the condenser asserubly 51 to -thereby enable the condensers 39 and 40 to be connected to a refrigerant pump down circuit 52. The three-way valves 42 and 43 are c0unected to the pump down conduit 52 which is in turn connected to the suctiou header 23 whereby any condensed refrigerant present in the condeuser coil 39 or 40 at the time either valve 42 01' 43 is closed from brauch c0nduits 38 will be evaporated and drawn back into the system by compressor 25 thereby reducing the quautity of refrigerant charge required in the system by eliminating this useless accumu lation of liquid refrigerant in these shut-down condenser coils 39 or 40.

The pressure regulating valves 46 and 47 are of the type which maintain a constaut upstream pressure thereby maintaiuiug a preselected ruinirnum refrigeraut pressure in the coudenser coils 39 and 40 during their Operation and, obviously, this will be the miniruum head pressure of the compressor 25. The pressure settiug of valves 46 and 47 will always be above the minimum desired liquid refrigerant line pressure of the refrigeration system as the receiver 13 and liquid lines 15 and 17; for example, with refrigerant 22 an optimum liquid liue pressure may be in the realm of 150 p.si. However, it will be understood that the pressure setting cf the valves 46 and 47 does not establish the liquid line pressure and that the head pressure must be high enough to force refrigerant condeused in the c0ndeusers 39 and 40 to the c0ndenser assembly 51. The exact setting of valves 46 and 47 will depend on the most economical condition that may be achieved in that partieular geographical location in which the system is iustalled, due 110 the relative cost of the electrical power for operatiug the compressor 25 and of the fuel which may be used to supplemeut the heatiug derived from coudenser co1ls 39 and 40. The higher the pressure setting of valves 46 and 47, the higher will be the head pressure thereby increasiug the ower cousumption cf compressor 25 but proportionally increasiug the heat which may be reclaimed by condeusers 39 and 40. However, if fuel costs are eatremely low then the lowest practical head pressure Will produce the most economical operation and therefore valves 46 and 47 may be set to maiutaiu a constant pressure at 0r slightly above the minirnum desired liquid line pressure of approximately 150 p.s.i.

Another pressure regulating valve 53 1s prov1ded -m the brauch conduit 54 cormected between header 50 leading to outside condenser assembly 51 and the discharge conduit 35 from the compressor 25. Pressure regulatmg valve 53 is adjusted to a pressure setting slightly i.uexcess of the setting cf regulating valves 46 and 47 whereby the head pressure 011 compressor 25 will uot exceed the setting of valve 53. Thus, for example, as the systemus 11- lustrated with coudenser coil 39 shut ofl, the capacrty of condenser coil 40 may not be suflicient to handle the full output of compressor 25 without unduly increasing the head pressure whereby the head pressure will tend to exceecl the value setting of valve 47. The valve 53 Will open when the head pressure reaches its value setting to pass some of the hot gaseous refrigerant directly to the outside condenser assembly 51 thereby providing adequate coudenser capacity and maintaiuing the head pressure of the compressor 25 between the seltings cf the valves 46, 47 and the valve 53.

When all of the interior heat-reclaiming condenser coils are shut down, such as during the warm summer months, then four-way valve 36 is shifted to a position for counecting discharge line 35 directly to header 50 rather than header 37 and this may be accomplished by an appropriate electrical circuit respousive to the thermostats 44 and 45 It will be understood that each thermostat 44 or 45 is independently responsive to demands for space heating for actuating its valve 42 or 43 to connect the respective condenser 39 or 40 to the header 37, and that the main refrigerant distributiug valve 36 must also be actuated by each thermostat 44 or 45 to counect the discharge line 35 to the header 37. Obversely, the valve 36 must be actuated to connect the discharge line 35 to the header 50 ouly when all of the interior condensers are in a uon-heatiug condition. When the four-way valve 36 com1ects the conduit 35 to the header 50, the header 37 is conuected to a pump down conduit 55 and a normally closed solenoid valve 56 is opened to counect the header 37 to the intake of the compressor 25 thereby evaporating and rernoviug the liquid refrigeiant which might otherwise accumulate in header 37 and brauch conduits 38. Again, this evacuation 01' pump down minimizes the quantity of refrigerant that might otherwise be required in the entire system to accommodate these various conditions of operatiou and also serves to prevent damage which might occur from forcing a quantity of accumulated refn'gerant through header 37 and the condenser coils upon returning the four-way valve 36 to the position shown in the drawiug. It is to be understood that solenoid valve 56 is closed 6 when four-vva'y valve 36 conuects the discharge 35 to header 37.

The outside condenser assembly 51 serves to condense the entire discharge cf the compressor 25 when four-way valve 36 cormects such discharge directly to header 50 or to coudense any portion of the refrigerant which asses through the heat-reclaiming condeuser coils 39 and 40 without being condensed. Thus, the capacity of outside condenser assembly 51 must be sufiicient to handle the complete compressor discharge under the warmest expected ambient couditions and yet must not roh the en tire refrigeratiou system cf the refrigerant charge by completely flooding during severely cold ambient conditions Wheu perhaps the entire refrigeraut discharge of compressor 25 is coudensed by the heat reclaiming condenser coils 39 and 40. T0 this end the outside condenser assernbly 51 is provided with a plurality of separate condenser coils, three of which are shown and designated 60, 61 and 62, connected in parallel relatiouship between the header 50 and a liquid refrigeraut line 63. The ambient air is circulated past the condenser coils 60, 61 and 62 by any canvenient means such as a fan 64 and such air circulation may be in either series 0r parallel relation through said condenser coils. Three condeuser coils are shown but it will readily appear to those skilled in the art that any number of parallel connected coils may be employed and additioual coils would normally be connected and controlled in a manuer similar to coil 61 or perhaps coil 62 as hereinafter described. All but one of the concleuser coils are connected to header 50 by means of a three-way valve which is pressure controlled. As shown in the drawiug, coil 60 is connected directly to heacler 50 and three-way valves 65 and 66 are provided between header 50 and condeuser coils 61 and 62, respectively. A pressure coutrol 67 responsive to the outside condenser pressure in header 50 operates the three-way valves 65 and 66 to successively close the three-way valves as the pressure drops below the minimum desired level which again clepends 011 the desired minirnum liquid line pressure. For example, as the pressure drops in header 50 below thepreselected value as might occur when part cf the condensing is being accomplished by the interior coudenser coils 39 and 40 or under 10W ambient conditions, the control 67 shifts valve 66 to the position shown in the drawiug thereby disconnecting coil 62 frorn header 50 and increasing the coudensing load upon the remaiuiug condenser coils 60 and 61, thereby causiug the outside condenser pressure to rise to the desired level. If the ambient temperature continues t0 drop and the combined capacity of condenser coils 60 and 61 is excessive whereby the pressure in header 50 drops below the desired level theu coutrol 67 shifts valve 65 to disconuect coil 61 from header 50 thereby reducing the capacity of outside coudenser assembly 51 to the single coil 60. The outlet of condeuser coil 60 is coutrolled by a pressure regulating valve 68 for maintaining a minimum pressure on condenser coil 60. Pressu-re regulatiug or throttling valve 68 is set to a value which Will cause partial flooding of condenser coil 60 as the outside condeuser pressure in header 50 begins to drop and before the valves 65 and 66 are shifted to disconuect condenser coils 61 and 62, thereby partially reducing the effective coudensing area of coil 60 thereby automatically adjusting the overall capacity of the outside condeuser assembly 51. As the pressure continues to drop and condenser coil 60 becornes uearly flooded then the pressure control 67 functions in the aforedesc1ibed manner to first shift valve 66 t0 discounect coil 62 to further decrease condenser capacity and iucrease pressure t0 reduce or eliminate the floodiug of coil 60 uutil the pressure again begins to drop.

Uuder intermediate conditions between the shifting of the valves 65 and 66 the coudenser coil 60 may be partially flooded thereby sub-cooling the liquid refrigerant leaving the coil and passing through the pressure regulating or throttling valve 68 to the liquid line 63. Subcooling of the liquid refrigerant is of well known advan tage and can resultinsubstantial power savingsif such sub-cooling is obtained without additional expenditure of power as is involved in the use of sub-cooler 16.

A-t leastone of the separate parallel condenser coils of the outside condenser assembly 51 may be connected to accomplish sub-cooling of the condensed refrigerant and, as shown in the drawi.ng, such coil should be the first coil to -be disconnected frorn the bot gas header by means of the pressure control 67. Condenser coil 62 is so counected whereby the shifting of three-way valve 66 counects the coil to a conduit 71 which is in turn connectecl to the liquid line 63 downstream of a solenoid valve 72. When valve 66 is shifted by control 67 to connect the coil 62 to conduit 71 the control 67 also serves to close solenoid valve 72 thereby causing the condensed refrigerant received from coils 60 and 61 to pass through coil 62 in a reverse direction and elfect suh-cooling cf such refrigerant. By this arrangernent of outside condenser assembly 51 the proper liquid line pressure is continually maintaiued (rather than requiring the inefficient introduction of hot gaseous refrigerant to the outlet of the condenser as in the past) and advantageous sub-cooling is automatically and efiiciently obtained uuder all but the hottest ambient conditions.

Condenser coil 61 is connected to line 63 through a heck valve 69 to prevent reverse flow through die coudenser coil when the valve 65 is shifted to disconnect the coil from header 50. In shifting valve 65 to disconnect condenser coil 61 from the header the valve connects the coil to a pump down line 70 connected t the intake cf com=pressor 25 whereby any liquid Iefrigerant accumulated within condenser coil 61 Will be evaporated and returned to the system, again minimizing the quantity cf refrigerant charge that might otherwise be required in this system. If the sub-cooling arrangement of the coudenser 62 is not needed or desired, the condenser 62 may be conneced to a pump down conduit similar to that cf the co-ndenser 61 Liquid line 63 is connected to liquid line 15 passing below and in communication With the surge-type receiver 13 to normally pass sub-cooled liquid refrigerant to the header 17 and also into the receiver 13. An important featureof this invent-ion is the maintenance of a liquid line pressure above a predetermined minirnum level. In .the refrigeration system disclosed, the evap0rators 18, 19 and 20 are defrosted by substautia'lly saturated gas -taken irom the top of the receiver 13 through header 29. Therefore, to maintain a constant supply to saturated gas in the receiver 13 and prevent condensation thereof due io the sub-cooled refrigerant delivered to the liquid line 15 (and while maintaining the liquid line pressure throughout the receiver), a temperature stratification 055 liquid refrigerant in the receiver 13 is provided in which the upper strata er layer of refrigerant is at the same temperature as the saturated gas and isolates the subcooled liquid from such saturated gas to prevent coudensation thereof. Conduit 75 is connecoed hetween the compressor discharge 35 and the top of the receiver 13, and a pressu.re regulating valve 7 9 is provided in conduit 75 and constitutes a minimum pressu-re control for maintaining a minimum pressure on the downstream side of the valve thereby maintaining a predetermined minimurn pressure inthe receiver 13 which pressure is adjusted to the desired liquid line pressure of the system. lf for any mason the pressure in receiver 13 drops helow the pressure setting of valve 79 as might occur during defrosting of one or more of the evaporators wheh valve 68 is throttled down or closes to maintain head pressure or when sub-cooled liquid refrigerant is drawn into the receiver 13 under conditions creatiug a high degree cf turbulence intermixing the warm insulating refrigerant strata therewith, then the valve 79 opens to maintain the minimum receiver pressure and maintain the relatively warmer upper strata of liquid refrigerant in the 8 receiver 13. An equalizing line having a check valve 81 is connected between the receiver 13 and the Condenser header 56 for equalizing the pressure therebetween if the outside condenser pressure in header 50 drops below pressure in receiver 13. By this entire arrangement the condensed refrigerant which may be subcooled in theaforederibed manner by the outside coudenser assembly 51 will pass through line 15 and by the gas separating chamber 14 and receiver 13 without mixing such sub-cooled liquid refrigerant with the refrierant in receiver 13 which may be at a much higher temperature. Of course, if the liquid refrigerant passing from line 15 to liquid header 17 is sub-cooled then the conventional sub-cooler 16 is 110 operated. Due t0 fluctuations in liquid refrigerant requirements by the evaporators the level in receiver 13 may vary, but by this arrangement the cold refrigerant will always be introduced at the bottom of the receiver and be withdrawn frorn the bottom cf the receiver tending to produce stratification of the liquid refrigera-nt into levels commensurate With its temperature.

By tha aforedescribed condenser arrangement it may be seen that any desired minimum quantity of heat may be reclaimed without adversely aliecting head pressures or requiring full capacity, interior cond'enser coils. Further, in accordance with the objects of the invention, the interior and exterior condensers cooperate to provide complete liquid line and head pressu're control in a precise and economical manner. One or more heat-reclaiming condenser coils of this arrangement may be associated With a conventional multizone heating and air conditioning uuit 41 even though such unit does not dis sipate the entire heat available 01' provide the entire condensiug requirements of the system and even though difl'erent or additional heat reclaiming coudensers, such as coil 39, -may be provided, as disclosed. As shown, a separate air conditioning system, generally designated 90, has an evaporator coil 91 positioned in the cooling section of the multizone unit 14. As is conventional, the air conditioning systern comprises a compressor 92, a condenser 93 and receiver 94 for supplying refrigerant to the evaporator coil 91. Further, as is conventional With a multizone type unit, a ventilating fan 95 asses air over the heating coil (which is the refrigeration condensing coil 40 in the present system) and c ooling coil 91 in relative quantities as controlled by the cooperable modulating dampers 96 and 97, respectively, which are shown in a position for accomplishing full heating. Shifting of the dampers 96 and 97 to an intermediate position or even a full cooling position does not adversely affect the operation of the main refrigeration system since the hot compressed refrigerant Will pass through condenser coil 40 without condensing due to the closed damper 96 and lack of air circulati0n across the coudenser and the un-' condensed refrigerant will eventually be condensed by the outside condenser assernbly 51.

Having fully described my invention, it is to be Understood that I d0 notwish to be limit-ed to the details herein described 0r shown in the drawing but my invention is of the full scope of the appended claims.

I claim:

1. A coudenser arrangement for a closed cycle refrigeration system of the type having a compressor, condenser and evaporator, compn'sing, first condenser means associated With a space to be heated, secoud condenser means adapted fordissipating heat from the system, conduit means connectiug said first and second conde'nser means in series and between the compressor and the evaporator, said second condenser means being of a suflicient capacity tocondense the entire gaSe0us refrigerant output of the compressor, said second condenserh1eans having plural condenser coils normally connected in parallel relationship, and valve means for successively disconnecting all but.one of said condenser coils from the, compressor in response t0 declining compress0r head pressure for successively reducing the condensing capacity and maintaining a desired minimum compressor head pressure.

2. A condenser arrangement for a closed cycle refrigeration system, compn'sing, a receiver means f01' liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor means for compressing the evaporated refrigerant, first condenser means associated With a space to be heated, seconcl condenser means exposed to atmospheric conditions for dissipating heat, conduit means connecting said first conclenser means in series between said compressor means and said second condenser for making the full heat load available to said first condenser means for heating the space, said second condenser means being of a suflicient capacity to condense the entire gaseous refrigerant output of the compressor means when 110 heating of the space by said first condenser means is required, said second condenser means having plural condenser coils normally connected in parallel relationship to said receiver means, and valve means for successively disconnecting.all but one of said condenser coils of said second condenser means from said compressor means for reclucing the condensing capacity and maintaining compresso1 head pressure.

3. A condenser arrangement fr a closed cycle refrigeration systern of the type employing a compressor, sondenser and evaporator means, comprising, a plurality of condenser coils connected in parallel relationship and exposed t0 fluctuating conditions for dissipating heat, Conduit means connecting said parallel condenser coils between the compressor and evaporator means, said comdenser coils being of a sufiicient aggregate capacity to condense the entire gaseous refrigerant output of the compressor, valve means for successively disconnecting all but one of said condenser coils to adjust the condenser capacity to a level commensurate with the heat being dissipated, and valve and conduit means for reconnecting at least one cf said disconnected condenser coils in sen'es With and downstream of the remaining condenser coils operatively cormected to the compressor for passing refrigerant through said reconnected coil for sub-cooling the coudensed refrigerant.

4. A condenser arrangernent for a closed cycle refrigeration system of the type employing a compressor, comdenser and evaporator means, comprising, a plurality of condenser coils connected in parallel relationship and exposed to fluctuating conditions for dissipating heat, conduit means connecting said parallel condenser coils between the compressor and evaporator means, said comdenser coils being cf a sufiicient aggregate capacity to condense the entire gaseous refrigerant output cf the compressor, valve means for successively disconnecting all but one 0f said condenser coils to adjust the condenser capacity to a level commensurate wlth the heat being dissipated, for reconnecting at least one of said disconnected condenser coils in series with and downstream of the remaining condenser coils connected to the compressor for sub-cooling the condenser refrigerant in sai dreconnected coil, and presure regulating valve means 011 the outlet cf the said one condenser coil which remains connected to the compressor for maintaining a preselected pressure in that coil by flooding that coil as required.

5. A condenser arrangement for a refrigeration system, cornprising, a receiver means for liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor means for compressing the evaporated refrigerant, first comdenser means associated with a space to be heated, pressure regulating valve means associated With said first condenser means for selectively controlling the pressure in said first condenser means, second condenser means exposed to ambient atmospheric conditions for dissipating heat, conduit means connecting said first condenser means in series between said compressor means and said second condenser for making the full heat load available to said first condenser means for heating the space, said second condenser means comprised of a plurality of condenser coils normally connected in parallel relationship to said receiver means, and valve means for successively disconnecting all but one of said condenser coils of said second condenser means from said compressor means when not required to accomplish the complete condensing.

6. A condenser arrangernent for a refrigeration system arranged for selectively reclaiming heat to heat an enclosed space, comprising, a receiver means for liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor means for compressing the evaporated refrigerant, first condenser means associated with the space to be heated, said first condenser means including a plurality of separate condenser coils connected in parallel, thermostatically controlled valve means operatively connected to each said separate condenser coil :for selectively passing gaseous refrigerant through the associated condenser coil as required for space heating, second condenser means associated with ambient atmospheric conditions for dissipating heat, conduit means connecting said first condenser means in series between said c0mpressor means and said second condenser for making the full heat load available to said first condenser means for heating the space, and pressure regulating valve means connecting said cornpressor means t0 said second C011- denser means for by-passing said first condenser means t0 prevent exceeding a maximum head pressure on said compressor means, said second condenser means being of a sufiicient capacity to condense the entire gaseous refrigerant output of the cornpressor means when no heating of the space by said first condenser means is required.

7. A condenser arrangement for a closed cycle refrigeration systern comprising, a receiver means for liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, cornpressor means for compressing the evaporated refrigerant, first condenser means associated with a space to be heated, said first condenser means including a plurality of separate condenser coils connected in parallel, thermostatically controlled valve means operatively connected t0 each said separate condenser coil f0r selectively passing gaseous refrigerant through the associated condenser coil as required for space heating, second conclenser means exposed to ambient atmospheric conditions for dissipating heat, conduit means connecting said first condenser means in series between said compressor means and said second condenser for making the full heat load available td said first condenser means fr heating the space, said second condenser means being of a sufiicient capacity to condense the entire gaseous refrigerant output of the compressor means when no heating of the space by said first condenser means is required, and pressure regulating valve means associated With said first condenser means for maintaining a predetermined pressure in said first condenser means during operation thereof.

S. A condenser arrangernent f0r a closed cycle refrigeration systern, comprising, a receiver means for liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor means for cornpressing the evaporated refrigerant, first condenser means associated with a space to be heated, second condenser means exposed to ambient atmospheric conditions for dissipating heat, means for selectively connecting said first condenser means in series between said cornpressor means and said second condenser as space heating is required, and said second condenser means being of a sufiicient capacity to condense the entire gaseous refrigerant output of the compressor means when no heating of the space by said 11 fii'st condenser means is required, said second condenser continuously connected in condensing relation in the refrigeration system and having the outlet cm1ected to said receiver.

9. A condenser arrangement for a closed cycle refrigeration system, cornprising, a receiver means for liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor means for compressing the evaporated refrigeraut, first condenser means associated With a space to be heated, second condenser means exposed to ambient atmospheric conditions for dissipating heat, means for selectively connecting said first condenser means in series between said compressor means and said second condeuser, said second condenser means being of a sufficient capacity to condense the entire gaseous refrigerant output of the compressor means when 110 beating of the space by said first condenser means is required,

and pressure regulating valve means 011 the outlet of' said first condenser means for maintaining a predetermined pressure in said first condenser means during operation thereof.

10. A condenser arrangement for a closed cycle refi'igeration system, comprisiug, a receiver means f0r liquid refrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor means for compressing the evaporated refrigerant, first condenser means associated With a space to be heated, second condenser means exposed to ambient atmospheric couditions for dissipating heat, conduit means connecting said first condenser rneaus in series between said compressor means and said second Condenser, said second condenser means being of a suificient capacity to condense the entire gaseous refrigerant Output of the compressor means when n0 heating of the space by said first condenser means is Iequired, and means iucluding a pressure regulating valve means counecting said compressor means to said receiver means f01' maintaining a predetermiued minium pressure in said receiver means for supplying liquid refrigerant to said evaporator means.

11. A condenser arrangernent for a closed cycle refrigeration system comprising, a receiver means for liquid relrigerant, evaporator means connected to said receiver means and producing a refrigerant heat load, compressor rneans for compressing the evaporated refrigerant, first condenser means associated with a space to be heated,

pressure regulating valve means associated with said first condenser meaus for selectively controlling the pressure in said first condenser means, second condenser means exposed to ambient atmospheric conditions for dissipab ing heat, conduit means connecting said first condenser means in series between said compressor means and said second condenser for making the full heat load available to said first condenser means for heating the space, pressure regulating valve means connecting said compressor means t0 said second condenser mens for by-passing said first condenser means t0 prevent exceeding a maxi mum head pressure 011 said cornpressor rneans, said sec0nd condenser means being of a suflicient capacity to condense the entire gaseous refri'gerant output cf the compressor means when n0 heating of the space by said first condenser means is Iequired, and means including a pressure regulating valve means connecting said compressor means to said receiver means for maiutaining a predetermined minimum pressure in said receiver means for supplying liquid refrigerant to said evaporator means.

12. A condenser arrangement for a closed cycle refrigeration system comprising, a receiver rneaus for liquid refrigerani, evaporator means connected to said receiver means and producing a refrigerant'heatload, compressor means for compressing the evaporated refrigerant, first condenser means associated with a space to be heated, pressure regulating valve means associated with said first condenser meaus for selectively controlling the pressure in said first condenser meaus, said first coudenser meaus including a plurality of separate condenser coils connected in parallel, thermostatically controlled valve means operatively connected to each said separate coudenser coil for selectively passing gaseous refrigerant through the associated condenser coil. as required for space heating, second condenser means exposed to ambient atmospheric conditions for dissipatiug heat, couduit means counecting said first condenser means in series between said compressor meaus and said second condenser for making the full heat load available to said first coudenser means for heating the space, pressure regulating valve means connecting said compressor means to said second condenser means for by-passing said first coudenser means to prevent exceeding a maximum head pressure on said compressor rneans, said second coudenser means being of a sufiicient capac'ity to condense the entire gaseous refrigerant output of the compressor means when no heating of the space by said first coudenser means is required, said second condenser means having plural condenser coils normally connected in parallel relationship to said receiver means, valve means for successively disconnecting all but one 0f said coudenser coils of said second condenser means from said compressor means for reduciug the condensing capacity and maintaining a preselected head pressure, and pressure regulating valve means on the outlet of the said one condenser coil which remains connected to the compressor for maintaining a preselected pressure in that coil by flooding that coil as required.

13. In a refrigeration system requiring a predetermined maximum condensing capacity, first condenser means having said predetermined maximum condensing capacity and continuously connected in condensing relation in the refrigeration system, second condenser means having a condensing capacity less than said predetermined maximum condensing capacity of said first condenser means, und means responsive to predeterrnined conditions for connecting said first and second condenser means in series refrigerant flow relationship with the outlet of said second condenser means conuected to the inlet of said first condenser rneans.

14. In a refrigeration system having compressor means, receiver meaus, evaporator means and a liquid header connecting said evaporator means to the bottom of said receiver means; condenser means between said compressor and receiver means for condensing bot gaseous refrigerant from said compressor means, means for operating said condenser rneaus in at least a partially flooded condition for sub-cooling condensed liquid refrigerant, means connecting said coudenser means to said liquid header at the bottom of said receiver means for conducting sub-cooled refrigerant to said liquid header and producing temperature stratification of liquid refrigerant in said receiver means With the coldest refrigerant zone being at the bottom of said receiver rneans, and

other means adapted to connect said compressor meaus with the top cf said receiver means f01' maintaining a predetermined miuimum pressure in said receiver means und liquid header aud for maintaining said temperature stratification of liquid refrigerant in said receiver means.

15. A condenser arrangement for selective reclamati0n of heat from a closed cycle refrigeration system, comprising a first condenser positioned to give up heat to the space to be heated, a second condenser positioned to reject und dissipate heat frorn the systern, said second condenser having a capacity for accomplishing the entire condensing requirement of the refrigeration system, and means for selectively connecting said first condenser in series relationship in the refrigeration system with the outlet cf said first condenser connected to the inlet of said sec0nd condenser.

16. A condenser arrangement for a refrigeration systern, comprising a plurality of condenser coils connected 13 14 to the refrigeration system in parallel relationship, all References Cited but one of said condenspr coils havin g va1ve means with UNITED STATES PATENTS control means for closmg and openmg each such condenser coil in response to condenser head pressure re- 1790237 1/1931 Klugspectively dropping or raising from the desired level, and 5 2,874550 2/1959 Mussonthe other said one condenser coil having a pressure 5/1964 Johnson responsive va1ve 011 the ouflet thereof for causing pres- 7/1964 Malkoff' sure controlled fiooding of said coil when the condenser 3257822 6/1966 Abbott 62 196 X head pressure drops below the desired level. MEYER PERLIN, Primary Examiner. 

1. A CONDENSER ARRANGEMENT FOR A CLOSED CYCLE REFRIGERATION SYSTEM OF THE TYPE HAVING A COMPRESSOR, CONDENSER AND EVAPORATOR, COMPRISING FIRST CONDENSER MEANS ASSOCIATED WITH A SPACE TO BE HEATED, SECOND CONDENSER MEANS ADAPTED FOR DISSIPATING HEAT FROM THE SYSTEM, CONDUIT MEANS CONNECTING SAID FIRST AND SECOND CONDENSER MEANS IN SERIES AND BETWEEN THE COMPRESSOR AND THE EVAPORATOR, SAID SECOND CONDENSER MEANS BEING OF A SUFFICIENT CAPACITY TO CONDENSE THE ENTIRE GASEOUS REFRIGERANT OUTPUT OF THE COMPRESSOR, SAID SECOND CONDENSER MEANS HAVING PLURAL CONDENSER COILS NORMALLY CONNECTED IN PARALLEL RELATIONSHIP, AND VALVE MEANS FOR SUCCESSIVELY DISCONNECTING ALL BUT ONE OF SAID CONDENSER COILS FROM THE COMPRESSOR IN RESPONSE TO DECLINING COMPRESSOR HEAD PRESSURE FOR SUCCESSIVELY REDUCING THE CONDENSING CAPACITY AND MAINTAINING A DESIRED MINIMUM COMPRESSOR HEAD PRESSURE. 